A new multizone airflow and contaminant dispersal model CONTAM93 is described, along with a demonstration of its application in a study of ventilation and contaminant control in single-family residential buildings. While CONTAM93 is based on existing theory of network airflow analysis and contaminant dispersal, the model employs a unique graphic interface for data input and display. The interface uses a sketchpad to describe the connections between zones and icons to represent zones, openings, ventilation system components, and contaminant sources and sinks.
A measurement system is described to record the movement in a room of neutral density balloons or bubbles, and thus the movement of air in that room. It is based on photogrammetric analysis of coincident video recordings made from several view points. Under laboratory conditions, the system was found capable of measuring position to an accuracy of +/-3cm over a range of 8m, andof measuring 3-D velocities to better than +/-0.05 m/s. The system was usable under field conditions, and could be operated in an occupied building. The largest space tested was approximately 30x15x10m.
This paper briefly reviews the weather data available for natural ventilation and briefly reviews hourly data for simulation. It starts by reviewing the need for basic data for initial manual calculations. It then discusses the hourly weather data available for example the UK CIBSE Example Weather Years, and the European Community Test Reference Years. These are mostly selected for energy analyses rather than design, but there is still aneed for establishing general criteria for weather data for design of HVAC services and natural ventilation.
Ventilation of the void below suspended timber floors is necessary to prevent dampness, which leads to wet and dry rot. The air flow beneath such a floor has been investigated for a range of ventilator hole positions, using a full-sized test room. The variations in heatlosses with ventilation rate have been measured, for floors with and without insulation. The use of radiation barriers in place of conventional thermal insulation was found to cut down the heat losses significantly at low ventilation rates, but was not so effective at higher rates.
The system of decentralized apartment ventilation has been successfully used for several years in multiple-storey apartment construction in the Federal Republic of Germany. With this tried and tested system, the individual apartments are vented into a common exhaust shaft with decentralized apartment ventilating fans. The special designs of the individual fans ensure a constant volume flow of the outgoing air in the individual apartments, in spite of the large pressure variations into the outgoing air conduits. Non-returnflaps prevent a back flow of the outgoing air.
The paper is presenting experience from a several year long time of operation in a group of apartment buildings in the Stockholm area, Sweden, having an extremely low energy usage, less that 110kWh/(m2.year), electricity supply to the building services included. The system solution used has a very low pressure drop in the exhaust ducts. Every exhaust point is connected to an individual duct leading to a fan chamber in the attic. The pressure in that chamber is kept constant.
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